Design And Research Of Turbo-driven High-speed Permanent Magnet Generator

High speed permanent magnet generator has the characteristics of small volume,high efficiency and high speed,it can be connected to the high speed device such as a turbine without a prime mover drive shaft drive,save the gear,and improve the efficiency of use of space.It has becoming the core component of mechanical energy into electricity in the automobile exhaust gas turbine power generation device.Because the efficiency of the generator directly determines the utilization of the vehicle exhaust gas,high power density per unit volume of the high-speed permanent magnet generator,making the electromagnetic load of the motor is high,so the selection of the size and structure of the traditional permanent magnet generator design method High speed generator is not accurate.Based on the coupled analysis of multiphysics,we determine the maximum outer diameter of the rotor,starting from the centrifugal force suffered by the rotor.In the choice of stator material,the stator slot shape,the number of slots,winding connection and diameter and other aspects of a reasonable choice of design of the stator,the same permanent magnet materials for the rotor,permanent magnet structure and magnetization method,the thickness of the permanent magnet,pole pairs,gas Gap length and other aspects of a reasonable choice.Based on the combination of the field and the road,the parameters of the primary motor are optimized.The 2D transient simulation of the high speed permanent magnet generator designed by finite element method is carried out.The distortion of sinusoidal waveform of the back-EMF voltage under parallel magnetization is less than the national standard,Build an external circuit,comparative analysis of air-gap flux density under load and load,the air gap flux density Fourier simulation analysis of waveform quality.The finite element method is used to calculate the main parameters of high-speed generator such as power factor and inter-pole magnetic leakage coefficient.The mechanism of stator core loss is explained by the Bertotti iron loss model,and the stator core loss is calculated numerically.The stator copper loss,wind friction loss and rotor eddy current loss are calculated and explained respectively.Based on the thick cylinder theory of elastic mechanics,the rotor strength under different limit conditions is calculated separately for the rotor 3D model,and the variation law of the rotor strength with different factors is obtained.Based on the combination of the rotor strength constraint and the elastic cylinder theory,Rotor composite sheath structure,and the composite sheath is optimized.The results show that with the change of the thickness of the sheath and the permanent magnet,the stress gradually decreases,and the shear stress of the permanent magnet is affected by the rotational centrifugal force because of the reason of the static interference.Under the condition of thermal state,the expansion of the material makes the contact force of the permanent magnet and sheath increase,the stress of the rotor is increased,the safety factor is the lowest,but the permissible stress range of the material is still in the same way,and the same nickel alloy sheath is used in the composite sheath.The rotor strength is very close to the single layer nickel alloy sheath in the case of the two layers,which are divided into 0.4mm.When the sheath thickness is reduced by 20%,the rotor eddy current loss decreases 11.5W,the stator core loss is slightly increased,and the motor efficiency is increased by 1.1%,which is beneficial to the heat dissipation.